VERIFIED SOLUTION i

MailStream Plus- When using the REPORT CRRTWALK (Walk-Sequence justification report) how do the counts and Saturation percentages get calculated?

MailStream plus - all versions, all platforms
The R FLAG parameter is used to tell MailStream Plus (MSP) if an address is Residential or not.   R FLAG can be set to look for an indicator in each Name-Address record of whether the record is Residential.  This information needs to be populated pre-MSP by a Coding application or other method.
Then ALG CR position 12=Z can be used to tell MSP to base residential saturation qualification on the true residential counts in the mailing.
MSP can then qualify saturation percentages most accurately.

If no R FLAG is used, then MSP first tries to qualify for Saturation by meeting 75% of the Total Delivery Stops on the Carrier Route.   
If it doesn't meet that 'Total' minimum, then MSP tests if it meets 90% of the number of residential stops on the Carrier Route in order to qualify. 

Rarely percentages over 100% of the delivery stops for a Carrier Route may be calculated.  
Most commonly this is because the ALG CR pos 26 has been set to N, so MSP is counting each record as a delivery stop.  The default value 'Y' is the more correct choice, because then MSP does not count multiple pieces to the same delivery stop in figuring Saturation percentages, which is per the DMM regulations.
Another reason incorrect percentages can occur is that the USPS's Delivery Counts table has not been updated when new addresses have been recently added in a Carrier Route.  Be sure to keep the CASS certification and Residential indicators as updated as possible to have the most recent and accurate CRRT information.
UPDATED:  August 29, 2017